01-python-foundations

Python Foundations for DevOps

The Python fundamentals you actually need for automation — variables, data types, conditionals, loops, and functions — used to build a real DevOps script: a system health checker that reads CPU, memory, and disk usage and compares them against thresholds.

What you'll learn

• Variables, data types, operators, and type casting
• if / elif / else, for and while loops
• Writing functions
• Reading live system metrics with psutil
• Basic try / except error handling

Setup

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

Files

• variables.py — variables, data types, operators
• control_flow.py — if/else and loops
• functions.py — functions
• system_health.py — the main one: CPU/memory/disk health report

python variables.py
python system_health.py

system_health.py prints something like:

=== System Health Report ===
CPU    : 12.4%  -> Healthy
Memory : 63.1%  -> Healthy
Disk   : 78.0%  -> WARNING (above 75%)
Overall: NEEDS ATTENTION

Practice

Write your own system_health.py from scratch:

1. Ask the user for a CPU threshold with input() and cast it to a number.
2. Read current CPU usage with psutil.cpu_percent(interval=1).
3. Print whether the CPU is healthy or over the threshold.
4. Bonus: also check memory (psutil.virtual_memory().percent) and disk (psutil.disk_usage("/").percent).
5. Bonus: wrap the input in try / except ValueError so bad input doesn't crash it.